Well, I laid down the crackpipe and I elaborated a theory for this.RnFR wrote:im not sure i understand what you are saying the reverse breakdown has to do with this whole equation. ii know that most of the characteristics on a diode datasheet are the max rating for voltage, current, temp, etc. but i'm not aware how those will fit into something like how they clip or rectify. is there some connection here? also i was aware of the different conduction knee points of diodes, but i don't think there is any proper way to measure this feature, is there? it doesn't seem to be something that is listed on a datasheet either. i'll try and do the experiment when i get a chance.
i could definitely hear the different capacitance of the diodes i tested as well. some of them seemed to cut a ton of low end, while others(Ge) seemed to pass plenty- especially when parallel.
I don't have an electronics degree so it's only guessins, but it may help.
Reading Ge diodes datasheets, it comes that Ge diodes have leaking currents in the uA range (microAmperes), while in silicons it's expected to be measured in picoAmperes, thousand time less circa.
In the circuit the current flowing in the final stage, after the diode, is also in the range of microamperes... you can tell doing some calculation: expecting a signal of some V peak to peak (say 4V for example), and having in this section an overall Z of 100K (assuming the Zin of the device connected after quite high), 4/100000=0.00004 A or 40 uA. So we are in the same current range and the currents interacts wtih each other.
Regarding the "noise pumping" effect, I would explain this way: between the capacitor and the diode after few cycles of signal a negative charge forms, until the voltage in that point reaches a negative value of the magnitude of V drop of the diode. When the guitar signal stops, since there is a negative voltage a DC current (the leaking current of the diode) begins to flow from the ground to the region, bringing with all AC signal with it (noise in this case). So the output is muted 'cause all AC noise, or part of it, flows to the more negative region. Once the negative charge is filled and the voltage returns to ground, no more current flow thru the diode and the noise reappears.
That's my 2 cents, don't take it like a scientific paper.